1. Field of the Invention
The present invention relates to an ink jet head and a method of manufacturing the ink jet head, the ink jet head ejecting ink drops through orifices from ink pressure chambers therein to perform a printing operation.
2. Prior Art
Some ink jet heads eject ink drops with the aid of bubbles generated by energizing heaters in the ink pressure chambers. Other ink jet heads disclosed, for example, in Japanese Patent Preliminary Publications No. 5-338156 and No. 6-8426, eject ink drops with the aid of a pressure generated by deformation of an ink pressure chamber.
These types of ink jet heads have a thin insulating coating formed on the inner wall of the ink pressure chamber. This coating prevents an electric current from flowing through the ink held in the ink pressure chamber when the ink is pressurized by the deformation of the chamber or generated bubbles.
The coating is, for example, a highly insulating silicone material having a low viscosity, and is formed by, for example, spin-coating where an insulating solution introduced into the ink pressure chamber is spread by a centrifugal force to form a layer of insulator on the inner wall of the ink pressure chamber.
After the thin coating has been formed, an orifice plate having orifices formed therein is bonded to the front end of the ink pressure chamber by an adhesive.
With the conventional method of manufacturing the ink jet heads, excessive insulating solution spreads over the front surface of the ink pressure chamber to which the orifice plate is to be bonded. Thin insulating coating materials such as silicone are highly water-repellent. Accordingly, when the orifice plate is bonded to the front surface of the ink pressure chamber, the bonding agent does not adhere to the surface on which the insulating coating remains deposited, or the adhesion of the bonding agent is very weak.